Integrity testing of storage tank structure using robotic ultrasound

Abstract

An objective of this invention is to provide apparatus and methods to test the integrity of empty and full tanks. Another object of this invention is to provide a granular inspection of the tank. Another object of this invention is to provide precision positioning information of sample points. Another object of this invention is to provide automated inspection pattern and correction. Another object of this invention is to minimize hazardous working conditions.

The invention claimed is: 
     
       1. A remotely operated vehicle (“ROV”) system configured to non-destructively inspect the integrity of an interior of a vessel, the system comprising:
 an ROV comprising at least one ultrasound transducer, tracks configured to assist the ROV to crawl on an inner surface of the vessel, and a plurality of thrusters configured to assist the ROV to swim through a liquid contained within the vessel; 
 an acoustic tracking system configured to track the location of the ROV in the vessel; and 
 a telemetry system configured to receive and compile data from the at least one ultrasound transducer and the acoustic tracking system, wherein the telemetry system is pre-loaded with a template of the interior of the vessel, including positions of floor plates and any obstacles. 
 
     
     
       2. The ROV system of  claim 1 , wherein the at least one ultrasound transducer is configured to measure both a floor and a wall of the vessel from a single position of the ROV. 
     
     
       3. The ROV system of  claim 1 , further comprising a plurality of ultrasound transducers. 
     
     
       4. The ROV system of  claim 1 , wherein the acoustic tracking system comprises at least one pinger and at least three hydrophone base stations. 
     
     
       5. The ROV system of  claim 4 , wherein the at least three hydrophone base stations are disposed on an outside of the vessel. 
     
     
       6. The ROV system of  claim 1 , further comprising a safety interlock comprising a pressure transmitter configured to continuously measure ambient pressure at the top of the ROV. 
     
     
       7. The ROV system of  claim 6 , wherein the safety interlock is configured to prevent the ROV, when descending into the vessel, from being powered until it is below a pre-determined exclusion zone. 
     
     
       8. The ROV system of  claim 6 , wherein the safety interlock is configured to prevent the ROV, when ascending from the bottom of the vessel, from being powered when it reaches a pre-determined exclusion zone. 
     
     
       9. The ROV system of  claim 6 , wherein the safety interlock further comprises a barometric pressure transmitter, located outside the vessel, that is configured to continuously measure ambient atmospheric pressure, and wherein the safety interlock is configured to accurately measure the depth of the ROV by taking into account the ambient atmospheric pressure. 
     
     
       10. The ROV system of  claim 1 , wherein the telemetry system is configured to time-stamp data generated by the at least one ultrasound transducer and data generated by the acoustic tracking system and correlate the data generated by the at least one ultrasound transducer and data generated by the acoustic tracking system with a position on the vessel. 
     
     
       11. The ROV system of  claim 1 , wherein the obstacles are selected from the group consisting of sumps, pipes, and a combination thereof. 
     
     
       12. A method of non-destructively inspecting the integrity of an interior of a vessel using an ROV system according to  claim 1 , the method comprising:
 providing an ROV in an interior of the vessel while tracking a location of the ROV in the vessel using an acoustic tracking system; 
 positioning the ROV at a measurement location in the vessel by moving the ROV by crawling on the interior surface of the vessel or swimming through a liquid contained in the vessel; 
 inspecting the measurement location using an at least one ultrasound transducer attached to the ROV and transmitting data generated to a telemetry exterior to the vessel; and 
 in the telemetry system, compiling data from the at least one ultrasound transducer and the acoustic tracking system to provide a measurement of the measurement location, wherein the telemetry system is pre-loaded with a template of the interior of the vessel, including positions of floor plates and any obstacles. 
 
     
     
       13. The method of  claim 12 , wherein positioning the ROV includes maneuvering the ROV around obstacles defined on the template. 
     
     
       14. The method of  claim 12 , wherein inspecting the measurement location includes using the at least one ultrasound transducer to measure both a floor and a wall of the vessel from a single position of the ROV. 
     
     
       15. The method of  claim 12 , wherein the ROV system further comprises a safety interlock system and the method further includes a step of preventing the ROV, when descending into the vessel, from being powered until it is below a pre-determined exclusion zone. 
     
     
       16. The method of  claim 12 , wherein the ROV system further comprises a safety interlock system and the method further includes a step of preventing the ROV, when ascending from the bottom of the vessel, from being powered when it reaches a pre-determined exclusion zone. 
     
     
       17. The method of  claim 12 , wherein the telemetry system is configured to time-stamp data generated by the at least one ultrasound transducer and data generated by the acoustic tracking system and correlate the data generated by the at least one ultrasound transducer and data generated by the acoustic tracking system with a position on the vessel.